Seasonality of bivalve larvae within a high Arctic fjord

Paid Open Acces

Seasonality of Meroplankton in Svalbard Waters

The temporal dynamics of meroplankton, manly comprised of larvae of benthic invertebrates that only temporarily inhabit the pelagic environment, is poorly understood in Arctic environments. The main objective of this thesis was to increase our knowledge on meroplankton dynamics and their ecological role in the Arctic marine coastal ecosystem. Three different approaches including high-frequency field sampling, molecular identification (DNA bar-coding, Bivalvia) and feeding experiments (Cirripedia nauplii) were applied to investigate the highly dynamic nature of meroplankton and how they relate to biological and environmental drivers and what might be their potential feeding impact during mass occurrences. Meroplankton contributed considerably to the total zooplankton abundance during the productive time of the year. A strong correlation of total meroplankton abundance with phytoplankton biomass was observed as a general pattern. We found that the timing of the spring bloom determined the onset of the “meroplankton-boost”, which mainly comprised Cirripedia and Bivalvia larvae. Strong seasonality was also found in the occurrence of the different bivalve larval species. The feeding experiments gave limited results, since the experimental set-up needs some improvements. Our investigation suggests that benthic invertebrate larvae play a significant role in the pelagic ecosystems in Arctic coastal regions, linking the pelagic and benthic realms. The different reproductive strategies of benthic invertebrates with planktonic larvae are discussed and some speculations about potential changes in a warming Arctic climate are made

Assessing the added value of the recent declaration on unregulated fishing for sustainable governance of the central Arctic Ocean

International audienceThe ‘Declaration concerning the prevention of unregulated high seas fishing in the central Arctic Ocean’ signed by the Arctic 5 nations, limits unregulated high seas fishing in the central part of the Arctic Ocean, and holds potential social, economic and political impacts for numerous stakeholders. In this paper, the four Interim Measures in the Declaration are discussed and what value these measures bring beyond the existing international agreements is explored. It is found that even though the Declaration fills a gap in the management of potential fish stocks in the central Arctic Ocean, adopts an appropriate precautionary approach and encourages joint research activities, there are both opportunities and challenges connected to its implementation. The most valuable and urgent Interim Measure is that of joint scientific cooperation, which will facilitate more region-specific research and an increased understanding of the fisheries as well as the broader Arctic environment. Furthermore, the research generated by this measure will provide an important decision base for both regulation and management of human activity in the Arctic